|Electric Defender research vehicle. Click to enlarge.|
Land Rover will unveil seven new battery-electric Defender research vehicles at the 2013 Geneva Motor Show. Although there are no plans for the all-terrain electric Defender to enter series production, the seven EVs will go into service in specialist real world trials later this year.
The standard 90 kW (121 hp), 360 N·m (265 lb-ft) 2.2-liter diesel engine and 6-speed manual gearbox in the 110 Defenders have been replaced by a 70 kW (94 bhp), 330 N·m (243 lb-ft) electric motor paired with a 27 kWh, 300-volt lithium-ion battery pack. Range is more than 50 miles (80 km). In typical, low speed off-road use it can last for up to eight hours before recharging. The battery can be fully charged by a 7kW fast charger in four hours, or a portable 3kW charger in 10 hours.
The electric vehicles (EVs) retain the Defender’s four-wheel drive system and differential lock. Because the electric motor delivers maximum torque from the moment it starts, there’s no need for gear shifting and the transmission comprises a single speed, 2.7:1 reduction gearbox combined with the existing Defender four-wheel drive system. A modified version of Land Rover’s Terrain Response System has also been incorporated.
The battery weighs 410 kg (904 lbs) and is mounted in the front of the Defender in place of the diesel engine. Curb weight is 100 kg (220 lbs) more than a basic Defender 110 and ranges from 2055 kg to 2162 kg (4,530 lbs to 4,766 lbs) depending whether the body style is a pick-up, hard top or station wagon.
All the major components in the electric powertrain—including the battery, inverter and motor—are air-cooled rather than liquid cooled, saving a considerable amount of weight and complexity and adding robustness.
Regenerative braking has been optimized to such an extent that using Hill Descent Control, the motor can generate 30 kW of electricity. Because the battery technology can be charged very quickly at a rate of up to twice its capacity of 54 kW without reducing battery life, almost all of the regenerated energy can be recovered and stored. Up to 80% of the kinetic energy in the vehicle can be recovered in this way, depending on conditions.
This project is acting as a rolling laboratory for Land Rover to assess electric vehicles, even in the most arduous all-terrain conditions. It gives us a chance to evolve and test some of the technologies that may one day be introduced into future Land Rover models.—Antony Harper, Jaguar Land Rover Head of Research
The vehicles were developed by Land Rover’s Advanced Engineering Team following successful trials of the Defender-based electric vehicle, Leopard 1.
(In 2011, Axeon and Jaguar Land Rover South Africa produced an all-electric version of the Defender model for use in game parks. The 28.8 kWh pack was fitted to a Land Rover Defender 110 High Capacity Pick Up with a 59 kW motor in place of the then standard 2.4-liter diesel—replaced by the 2.2 liter in the subsequent model year.)
The vehicles’ capability has been tested in extreme and environmentally sensitive conditions, demonstrating capabilities not shared by conventional road-going EVs. Trials included pulling a 12-tonne ‘road train’ up a 13% gradient and wading to a depth of 800mm (31.5 inches).